• Membre d'un pool d'experts
• Responsable de formations
• Responsable de diplôme (M2)

• Physique/Physique des Hautes Energies - Phénoménologie
  

We study regions in the parameter space of the NMSSM which are able to simultaneously explain the current measured values for the W mass MW and the muon anomalous magnetic moment aμ, and provide a dark matter relic density consistent with the observations as well as constraints from detection experiments. The corresponding regions feature light charginos, sleptons and staus in the 100-600 GeV range, at least some of them with masses below 150 GeV such that the electroweakly-interacting SUSY particles generate sufficiently large contributions to MW. The LSP is always singlino-like with a mass below 140 GeV, and could possibly remain invisible even at future detection experiments. De- cays of electroweak sparticles proceed through cascades via staus and/or sleptons which makes their detection challenging. The lightest CP-even scalar may have a mass in the 95-98 GeV range with, however, modest signal rates in view of the mild excesses reported in this range at LEP and by CMS at the LHC.

We present benchmark planes (or lines) with cross sections via gluon fusion for the processes H → h+HBSM , resonant Higgs pair and triple Higgs production, and A → Z+h, A → Z + HBSM within the Next-to-Minimal Supersymmetric Standard Model. Moreover ̄ we propose new searches for H → h+(HBSM → tt), A → Z +(HBSM → h+h) ̄ and A → Z + (HBSM → tt) for which possible cross sections are given. These allow the experimental collaborations to verify in the future which search channels cover yet unexplored regions of the parameter space. Expressions for the dominant contributions to trilinear Higgs couplings and Higgs–Z couplings are discussed which allow to identify the dominant processes contributing to a given final state.

A light singlino is a promising candidate for dark matter, and a light higgsino is natural in the parameter space of the NMSSM. We study the combined constraints on this scenario resulting from the dark matter relic density, the most recent results from direct detection exper- iments, LEP and the LHC. In particular limits from a recent search for electroweak production of charginos and neutralinos at √s = 13 TeV after 35.9 fb−1 by CMS and constraints on spin-independent dark matter-nucleon cross sections from XENON1T after one tonne × year exposure are considered. We find that scenarios with higgsino masses below ∼ 250 GeV as well as singlino masses below ∼ 100 GeV are strongly constrained depending, however, on assump- tions on the bino mass parameter M_1. Benchmark points and branching fractions for future searches at the LHC are proposed.